Why Use Marine Aragonite? It is a pure Marine Aragonite sand collected from the crystal clear oceans of The Bahamas, with no harmful tar, organics or impurities. Aragonite is part of a hermit crabs natural habitat and they will feel right at home with this superior substrate. Hermit Crabs are land crustaceans and spend their adult lives on sandy dunes, rocky beaches and mangroves. Hermit Crabs are not recognized as true crabs because they lack a broad flat shell. They have an omnivorous diet consisting of vegetable matter and carrion in the wild. They love to climb and clamber over dried driftwood placed in the middle of their enclosure. These crustaceans are exceedingly docile, only nipping with their pincers in self-defense.